This invention relates generally to an animal isolation and caging system, and more particularly to an open rack system which maximizes both cage density within the rack and useful volume within each cage while providing protection for both personnel attending to the system and the animals contained within the cages from the contamination of the cages themselves and from the release of allergens, dander or other contaminants from an individual cage or rack system housing a plurality of cages through the use of a canopy capture system.
Animal isolation and caging systems are well known in the art. Such systems include the animal isolation and caging systems provided for in the ventilated rack systems disclosed in U.S. Pat. Nos. 5,349,923 and 5,165,362 assigned to Lab Products, Inc., in which an open rack system including a plurality of shelves, each formed as an air plenum, is provided. Air ventilation is provided directly to animals within each cage assembly by allowing air to travel within each shelf to a plurality of predetermined positions within the rack. At least one cage level barrier having a filter cap is positioned in a rack, so that the rack and the air conduits integral within it removes air disposed adjacent the filter cap. A cage guide is formed in substantially the same shape as the filter cap and is affixed to the bottom of a shelf of the rack holding a cage so that when the barrier cage is placed within the ventilated rack, it is positioned within the cage guide. The cage guide is separated from the filter cap of a cage by a distance. The air plenum shelf is provided with a vacuum to partially remove gases, dander, allergens and other compounds that originated in one or more cages and moving to a location outside the cage.
The prior art animal isolation and caging systems are satisfactory. However, because each shelf acted as an air plenum, each shelf required a certain height within the rack to allow for air to travel therethrough, and due to a lack of a enclosed canopy or other gas capture system, animals as well as workers maintaining cages could be exposed to high levels of allergens, disease causing agents, inappropriate chemical signaling agents (e.g., pheromones), dander or other undiserable compounds released from the animal cages themselves or present in the air in proximity to the cages. The answer provided by the prior art was to proportion the combined height of each shelfband the cage guides mounted below each shell to maximize vertical cage density, thereby maximizing the effect of negative pressure removal of contaminants, without providing for a means of creating a capture system for contaminants. Another problem provided by such prior art systems is the use of large amounts of opaque material or metal that hinder visual inspection of a high cage density rack system. A system that provided a xe2x80x9csee throughxe2x80x9d system that would allow an operator to more easily determine the condition of individual animals and the environment in individual cages.
Filter cap assemblies for animal cages used within animal isolation and caging systems are also well known in the art. One such filter cap is disclosed in U.S. Pat. No. 4,640,228, assigned to Lab Products, Inc., in which a top body with a perforated filter cap top wall is provided. A sheet of filter material is sandwiched between a retainer and the lower surface of the perforated filter top wall of the top body. The retainer is detachably mounted inside the filter body in flush abutment with the filter material placed against the lower surface of the filter top wall of the top body. The retainer comprises a narrow border portion and flat cross arms which intersect at an integral central portion.
This prior art filter top was satisfactory. However, because the retainer was secured to the filter cap body on the interior of the filter cap body, changing a filter with an animal within the cage was inhibited because the entire filter cap required removal from the cage to remove the retainer and change the filter. Moreover, because the retainer was substantially open, the bottom side of the filter was substantially exposed to animals within the cage who might damage the filter, rendering it ineffective and resulting in contamination or requiring additional an structure such as a wire bar lid for protection of the filter.
Another solution to the filter changing problem is found in U.S. Pat. No. 5,797,349, assigned to Lab Products, Inc., in which a filter changing station is provided in which the filter protecting an individual cage can be changed without opening the entire cage. The changing station disclosed in this prior art is, however, difficult to operate and often results in the ripping of a used filter or the improper placement of a new filter in the filter cap.
Another such filter cap is enclosed in U.S. Pat. No. 4,480,587, assigned to Lab Products. Inc., in which a cap body with an open top portion provided with a ledge and cross arms is provided. A filter Is detachably secured to the cap body by an overlaying protective plate member which is fastened over the ledge and cross arms using a plurality of fasteners, such as threaded bolts which pass through holes in the plate member, filter and cap body and secured by respective nuts.
This prior art filter cap was also satisfactory. However, because separate threaded bolt fasteners were used to mount the protective plate to the filter cap body, personnel changing a filter were required to use special tools to remove the protective plate to release the filter. The use of such tools required additional resources and was time-consuming. Moreover, because the cap body had a substantially open top and no specific filter frame, the bottom side of the filter in this design was also unprotected from animals within the who might damage the filter and render it ineffective during a filter changing operation. In addition, the substantially open top inhibited changing a filter with an animal within the cage because of the possibility that the animal could escape through the open top of the cage body during a filter changing procedure.
Typically, the cages in a rack system must be removable from the rack system to provide access to the animals for feeding and testing, and to the cages for cleaning, maintenance and transport. However, it also required that the rack air source and/or water source mate with the cage to provide air and water to the cage. To accommodate this requirement it is known in the art to provide a structure so that the valve in each cage is connected to an air and/or water plenum on the rack by a coupling system. In such a system, each cage is connected to the plenum by pushing the cage into a rack until the coupling at the rear of the cage is connected to the coupling provided on the plenum to make mating contact with a valve system containing connections to water and air sources. The couplings are disengaged by simply pulling the cage out of the rack, which closes a valve within the plenum coupling to prevent the escape and contamination of water and air.
In the prior art, cages designed for ventilated cage and rack systems also failed to provide for securely dividing a cage between two or more animals. The designs provided in the prior art, as typified by U.S. Pat. No. 6,041,741, assigned to Lab Products Inc., disclose only one source of food and water respectively within a given cage. This may be undesirable in those situations where it is desirable to more effectively utilize a cage footprint in compliance with appropriate federal guidelines and increase occupancy of a given caging system, or in situations where dividing animals is necessary for research ends"" or the animals"" welfare. Accordingly, it is desirable to provide a double-sided ventilated caging system including a cage-level barrier cage with a specific footprint that complies with appropriate federal guidelines while simultaneously being available to house a multiplicity of different animals typically used in scientific studies and separate them into at least two compartments through use of a removable divider element that is contoured to the cage system and will prevent any caged animals from gaining purchase on the divider and chewing through it or otherwise damaging it. The compartments formed as a result of the removable divider element being provided with individual food and water sources.
Filter top locking mechanisms have also been designed to prevent an individual cage from being opened from within by an animal held there or accidentally opening when a worker uncouples a cage from the plenum and the rack in which it is located. However, these prior art designs have been large, cumbersome and expensive. Accordingly, it is desired to provide a simple, self-contained animal cage locking mechanism which enables an operator to lock a cage and keep it securely sealed yet easily manipulated by a worker handling individual cages who needs to maintain the cages and/or the animals within them. Such a locking mechanism should maintain engagement despite bumping, jarring or improper removal of an individual cage, and which should also be less cumbersome and more easily replaced if lost or damaged.
Accordingly, it is desired to provide a animal isolation and caging system which maximizes the stacking density of cages within the rack, while providing for the removal of unwanted contaminants from circulating in a laboratory environment, in the rack system itself, and among cages. It is also desirable to provide a double-sided ventilated caging system including cage-level barrier cages that minimize the use of opaque materials or metal which hinder visual inspection of a animal isolation and caging system. It is also desired to provide a modified filter cap for animal cages used in a animal isolation and caging system which permits easy changing of the filter while an animal is within the cage and which protects the filter in use and the filter top itself from damage caused by animal(s) housed in an individual cage. It is also desired to provide a cage design footprint that will house up to two full grown rats in compliance with appropriate lateral regulations, such a cage design also providing for a divider element that securely divide the cage into at least two equal compartments, each compartment having an individual food and water source. It is further desired to provide a simple animal cage locking mechanism which enables an operator to securely move, transport, or manipulate an individual cage that is itself easily and inexpensively replaced.
Generally speaking, in accordance with the instant invention, an animal isolation and caging system which maximizes cage density while minimizing the use of opaque materials and metal within a ventilated rack is provided. The rack includes at least one air exhaust plenum, and at least one canopy disposed within the rack for ventilation of the cages housed in a rack system. The rack is capable of supporting a first cage within the rack below a first canopy, and also positioning a second cage below a second canopy. The filter top of the first cage provided by the invention also provides a filter retainer having a filter top retainer wall designed to be in contact with a first canopy unit forming an enclosed space so configured as to create an enclosed space from which the animal isolation and caging system of the invention creates a zone of negative pressure so as to permit air to be drawn into an air exhaust plenum or duct from the interior of the first cage through the top of the first cage.
Generally speaking, in accordance with the instant invention, a filter cap for an open-top cage is further provided. The filter cap includes a substantially rigid filter frame bonnet adapted to cover the open top of the open-top cage. The filter frame bonnet includes a body portion with a perforated top, and side-walls extending therefrom forming an open bottom end. The filter cup also includes a substantially rigid filter retainer sized to fit upon the filter frame bonnet and to substantially cover the perforated top of the filter frame bonnet, the filter retainer also having a filter top retainer wall. The filter retainer includes a top end with perforations so as to allow the passage of air, and side walls extending from the top end of the filter retainer forming an open bottom end, the perforations in the filter retainer being substantially in alignment with the perforations in the filter frame bonnet when the filter retainer is mounted on the top of the bonnet. The filter cap further includes attachment means for detachably securing the filter retainer to the rest of the filter cap body to permit enclosure of a sheet of filter material therebetween, the attached means being integrally formed in the bonnet and the filter retainer, typically, being configured as snap rivets and or detents formed in a molded cage body.
Generally speaking, in accordance with the instant invention, the filter cap is further configured to provide for a detachable filter top lock designed to secure the filter cap to the cage body of the invention. The filter top lock being easily released by an operator, it being readily apparent as to whether a cage is properly secured. The filter top lock of the invention enabling an operator to securely move, transport, or manipulate an individual cage. The filter cap of the current invention also includes a chew shield configured to securely attach to the filter cap through the use of a plurality of snap rivets. The chew shield being designed to cover the open top of the cage body and able to prevent animals from having access to and/or damaging the filter frame, filter or filter retainer. The chew shield further having perforations substantially in alignment with the perforations in the filter frame.
Accordingly, it is an object of the invention to provide a animal isolation and caging system which maximizes the density of cages and animals housed within a ventilated rack system. To maximize animal density the current invention provides for a double-sided ventilated caging system including cage-level barrier cage with a specific footprint that complies with appropriate federal guidelines while simultaneously being available to house at least two large rats of the type used in scientific studies and separate them into at least two compartments through use of a removable divider element that is contoured to the cage system and will prevent any caged animals from gaining purchase on the divider and chewing through it or otherwise damaging it. The compartments formed as a result of the removable divider element being provided with individual food and water sources.
Another object of the current invention being to provide a double-sided ventilated caging system including cage-level barrier cages that, minimizes the use of opaque-materials or metal which hinder visual inspection of the animal isolation and caging system of the invention.
Another object of the invention is to provide a animal isolation and caging system which does not require distinct shelving for positioning and supporting cages within the rack and which thereby maximizes the proportion of space within the rack which may be occupied by cages.
Another object of the invention is to provide for a rotatable dosage feeder for an animal cage which slectively provides multiple exact dosages of food to an animal within a cage of the invention. The feeder has a frame dividing a cage interior side from a cage exterior side. A food holding member is rotatably mounted on the frame and holds a plurality of measured dosages of food. At least a portion of the food holding member extends within the cage to the cage interior side of the frame. In a preferred embodiment the food holding member is a carousel.
A further object of the invention is to provide a animal isolation and caging system with canopies which position and support cages within the rack without additional shelving and which, through canopy capture system, guide exhaust air drawn from cages within the rack through a canopy capture system into an air exhaust duct to remove exhaust air from the rack without contamination of operating personnel or cross-contamination between cages within the rack.
Still another object of the invention is to provide a filter cap for an open-top cage which permits a filter to be securely mounted yet easily and quickly changed with a filter removal device easily utilized by an operator.
A still further object of the invention is to provide a filter cap for an open-top cage which permits replacement of a filter while animals are within the cage and which prevents such animals from escaping during filter replacement.
Yet another object of the invention is to provide a filter cap for an open-top cage which protects the filter from damage caused by animals within the cage through the use of a chew shield.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specifications and drawings. The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts which will be exemplified in the constructions hereinafter set forth, and, the scope of the invention will be indicated in the claims.